Open Pegasus, make sure you are working on a new file and you do not have an old file opened, you cannot change blade diameter after shapes have been placed on the slab.
Open configure tools and technology, if the icon is greyed out it's because shapes have been placed on the slab, it is not possible to edit blade if shapes are on the table, delete the shapes or make a new file.
on the left side it's the material to be cut by the blade, materials are selected when the slab is created, it is easier to manage only one material if you cut everything the same way with the same blade, otherwise create different materials with different blades and cutting settings.
click on the edit tool in the disk cutting section
¶ Diameter
The diameter of the blade is very important to set this parameter to be close to the real diameter of the blade, even tough the machine does probe the blade, this is only for fine adjustments, cutting trajectory are still planned according to diameter specified here
¶ Core thickness
The thickness of the metal part of the blade, this parameter can effect the position of the blade on the machine, if not set properly when the head spins 180 degree the machine will not cut properly, also read here for more details
¶ Segment thickness
The thickness of the diamond part of the blade, it affects all cuts, if parts are not cut in size no matter of head position check this parameter and set properly, a precise way to set is to cut a stone and measure the cut with a caliper, also read here for more details